Optimization modeling of superelevation rates based on operation speed

According to an accident investigation of twenty expressways in China from 2001 to 2007, the author found that only about 3.56 of all crashes involve rollover accidents and considering the severity of rollover accidents, the percentage of people that died from rollover crashes is nearly 40.5. However, the current Design Specification in China only specifies the maximum superelevation rates for different design speeds, and does not provide suggested value for certain traffic conditions. Moreover, the National Highway Traffic Safety Administration has proposed the concept of the static stability factor, which can provide new research thinking for the superelevation model. Therefore, this paper built an optimization model considering it's compatibility for different vehicle types, different design speeds and different curve radius. Moreover, the paper demonstrated the detailed calculation process of the optimization method on the basis of this data through an example. © 2010 ASCE.